ID   TX21A_PHOKE             Reviewed;          45 AA.
AC   P83895;
DT   19-JUL-2004, integrated into UniProtKB/Swiss-Prot.
DT   19-JAN-2010, sequence version 2.
DT   25-MAY-2022, entry version 33.
DE   RecName: Full=U1-ctenitoxin-Pk1a;
DE            Short=U1-CNTX-Pk1a;
DE   AltName: Full=Neurotoxin PKTx19C5;
OS   Phoneutria keyserlingi (Brazilian wandering spider) (Ctenus keyserlingii).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Entelegynae; Lycosoidea; Ctenidae; Phoneutria.
OX   NCBI_TaxID=272754 {ECO:0000305};
RN   [1]
RP   PROTEIN SEQUENCE, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, AND MASS
RP   SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=16278100; DOI=10.1016/j.cbpc.2005.09.010;
RA   Richardson M., Pimenta A.M., Bemquerer M.P., Santoro M.M., Beirao P.S.,
RA   Lima M.E., Figueiredo S.G., Bloch C. Jr., Vasconcelos E.A., Campos F.A.,
RA   Gomes P.C., Cordeiro M.N.;
RT   "Comparison of the partial proteomes of the venoms of Brazilian spiders of
RT   the genus Phoneutria.";
RL   Comp. Biochem. Physiol. 142:173-187(2006).
RN   [2] {ECO:0000305}
RP   PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, AND
RP   VARIANTS LEU-8; ASP-35; ASP-36; THR-39 AND ASN-43.
RC   TISSUE=Venom;
RA   Richardson M., Pimenta A.M.C., Bemquerer M.P., Santoro M.M.,
RA   Figueiredo S.G., Cordeiro M.N.;
RT   "Neurotoxin PKTx19C5 from venom of Brazilian wandering spider Phoneutria
RT   keyserling has sequence similarity with PNTx3-3 from Phoneutria
RT   nigriventer.";
RL   Submitted (APR-2004) to UniProtKB.
CC   -!- FUNCTION: Neurotoxin. Causes rapid general flaccid paralysis and death
CC       in mice at dose levels of 5 ug per mouse. {ECO:0000269|Ref.2,
CC       ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:16278100,
CC       ECO:0000269|Ref.2, ECO:0000305}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000269|PubMed:16278100, ECO:0000269|Ref.2, ECO:0000305}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000250}.
CC   -!- MASS SPECTROMETRY: Mass=5101.8; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:16278100};
CC   -!- SIMILARITY: Belongs to the neurotoxin 02 (plectoxin) family. 01 (Tx3)
CC       subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P83895; -.
DR   SMR; P83895; -.
DR   ArachnoServer; AS000217; U1-ctenitoxin-Pk1a.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Knottin; Neurotoxin; Secreted;
KW   Toxin.
FT   CHAIN           1..45
FT                   /note="U1-ctenitoxin-Pk1a"
FT                   /id="PRO_0000087632"
FT   DISULFID        3..16
FT                   /evidence="ECO:0000250"
FT   DISULFID        10..25
FT                   /evidence="ECO:0000250"
FT   DISULFID        15..34
FT                   /evidence="ECO:0000250"
FT   DISULFID        27..32
FT                   /evidence="ECO:0000250"
FT   VARIANT         8
FT                   /note="K -> L"
FT                   /evidence="ECO:0000269|Ref.2"
FT   VARIANT         35
FT                   /note="E -> D"
FT                   /evidence="ECO:0000269|Ref.2"
FT   VARIANT         36
FT                   /note="E -> D"
FT                   /evidence="ECO:0000269|Ref.2"
FT   VARIANT         39
FT                   /note="K -> T"
FT                   /evidence="ECO:0000269|Ref.2"
FT   VARIANT         43
FT                   /note="H -> N"
FT                   /evidence="ECO:0000269|Ref.2"
SQ   SEQUENCE   45 AA;  5033 MW;  53EE38F810CCF673 CRC64;
     GKCADAWKSC DNLPCCVVNG YSRTCMCSAN RCNCEETKKL REHFG